Each integrated circuit (IC) can be made up of billions of interconnected devices, such as transistors, resistors, capacitors, and diodes, located on one or more layers of an IC. These interconnected devices are often electrically connected with interconnect structures that include copper wires and tungsten contacts. Copper wires require a diffusion barrier liner to prevent migration of copper atoms into adjacent layers such as dielectrics, semiconductors or conductors. Greater scaling and sophistication of the ICs requires smaller wires. As the copper wire widths have become smaller, the impact of resistance by the liner has becomes greater.